Import sqlalchemy session/models/utils

Bring in session, base model, utilities, and tests for sqlalchemy
from Nova.

Add sqlalchemy to pip-requires and and python-mysql to test-requires.

Partially implements blueprint common-db

Change-Id: I3e0065cdac87e10c4e0742d66c293c72bb3acbb2

1 files changed, 103 insertions, 0 deletions

diff --git a/openstack/common/db/sqlalchemy/models.py b/openstack/common/db/sqlalchemy/models.py
new file mode 100644
index 0000000..e2eee28
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+++ b/openstack/common/db/sqlalchemy/models.py
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+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright (c) 2011 X.commerce, a business unit of eBay Inc.
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# Copyright 2011 Piston Cloud Computing, Inc.
+# Copyright 2012 Cloudscaling Group, Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+"""
+SQLAlchemy models.
+"""
+
+from sqlalchemy import Column, Boolean
+from sqlalchemy import DateTime
+from sqlalchemy.orm import object_mapper
+
+from openstack.common.db.sqlalchemy.session import get_session
+from openstack.common import timeutils
+
+
+class ModelBase(object):
+    """Base class for models."""
+    __table_initialized__ = False
+    created_at = Column(DateTime, default=timeutils.utcnow)
+    updated_at = Column(DateTime, onupdate=timeutils.utcnow)
+    metadata = None
+
+    def save(self, session=None):
+        """Save this object."""
+        if not session:
+            session = get_session()
+        # NOTE(boris-42): This part of code should be look like:
+        #                       sesssion.add(self)
+        #                       session.flush()
+        #                 But there is a bug in sqlalchemy and eventlet that
+        #                 raises NoneType exception if there is no running
+        #                 transaction and rollback is called. As long as
+        #                 sqlalchemy has this bug we have to create transaction
+        #                 explicity.
+        with session.begin(subtransactions=True):
+            session.add(self)
+            session.flush()
+
+    def __setitem__(self, key, value):
+        setattr(self, key, value)
+
+    def __getitem__(self, key):
+        return getattr(self, key)
+
+    def get(self, key, default=None):
+        return getattr(self, key, default)
+
+    def __iter__(self):
+        columns = dict(object_mapper(self).columns).keys()
+        # NOTE(russellb): Allow models to specify other keys that can be looked
+        # up, beyond the actual db columns.  An example would be the 'name'
+        # property for an Instance.
+        if hasattr(self, '_extra_keys'):
+            columns.extend(self._extra_keys())
+        self._i = iter(columns)
+        return self
+
+    def next(self):
+        n = self._i.next()
+        return n, getattr(self, n)
+
+    def update(self, values):
+        """Make the model object behave like a dict."""
+        for k, v in values.iteritems():
+            setattr(self, k, v)
+
+    def iteritems(self):
+        """Make the model object behave like a dict.
+
+        Includes attributes from joins."""
+        local = dict(self)
+        joined = dict([(k, v) for k, v in self.__dict__.iteritems()
+                      if not k[0] == '_'])
+        local.update(joined)
+        return local.iteritems()
+
+
+class SoftDeleteMixin(object):
+    deleted_at = Column(DateTime)
+    deleted = Column(Boolean, default=False)
+
+    def soft_delete(self, session=None):
+        """Mark this object as deleted."""
+        self.deleted = True
+        self.deleted_at = timeutils.utcnow()
+        self.save(session=session)